Brain Tumors

Differential diagnosis

• Low grade astrocytoma• High grade astrocytoma (Glioblastoma)• Meningioma• Oligodendroma• Brain abscess• Lymphoma• Schwannomas

High grade astrocytoma (Glioblastoma)

Clues to diagnosis: Astrocytoma

• Heterogenous mass• often infiltrate into adjacent brain• rarely have the clear margins

Oligodenroglioma

Clues to diagnosis: Oligodendroglioma

• Evidence of calcification in 30% of cases.

CNS lymphoma

Proton density–weighted MR image through the temporal lobe demonstrates a low signal intensity nodule (small arrows) surrounded by a ring of high signal intensity edema (larger arrows).

T1-weighted contrast-enhanced axial MRI demonstrates ring enhancement surrounded by a nonenhanced rim of edema. In this patient with AIDS, a solitary lesion of this type is consistent with either lymphoma or toxoplasmosis; the presence of multiple lesions favors toxoplasmosis

Meningioma

Clues to diagnosis: Meningioma

• Does not usually invade the brain• uniform contrast enhancement is essentially

diagnostic.• May have a dural tail.

Schwannomas

Axial noncontrast MR scan through the cerebellopontine angle demonstrates an extraaxial mass that extends into a widened internal auditory canal, displacing the pons (arrows)

Schwannoma

Postcontrast T1-weighted image demonstrates intense enhancement of the vestibular schwannoma (white arrow). Abnormal enhancement of the left fifth nerve (black arrow) most likely represents another schwannoma in this patient with neurofibromatosis type 2.